USP34-31-VOLUMETRIC-APPARATUS-容量仪器(中英文)

1、USP 34 VOLUMETRIC APPARATUS 容量仪器 Most of the volumetric apparatus available in the United States is calibrated at 20, although the temperatures generally prevailing in laboratories more nearly approach 25 . To minimize volumetric error, the temperature should be the same for the volumetric apparatus

2、, the material being prepared, the solvents being used to prepare the volumetric solutions, the area in which they are prepared, and the final volume adjustment.尽管实验室一般控制温度在25左右，但大部分容量仪器在美国可以在20校正。为减小容量误差，容量仪器、准备的材料、用于制备滴定液的溶剂、制备所在空间环境、最终调整体积的空间环境的温度应保持相同，Use To attain the degree of precision requir

3、ed in many Pharmacopeial assays involving volumetric measurements and directing that a quantity be “accurately measured,” the apparatus must be chosen and used with care. A buret should be of such size that the titrant volume represents not less than 30% of the nominal volume. Where less than 10 mL

4、of titrant is to be measured, a 10-mL buret or a microburet generally is required.使用 - 为达到药典含量所用容积测量要求的精密度，及达到“准确衡量”所要求的定量的精密度，容量仪器必须谨慎选择和使用。选择的滴定管规格应使用滴定液消耗体积不超过滴定管标示体积的30%，如果滴定体积小于10ml，一般要求使用10ml的滴定管或微量滴定管。The design of volumetric apparatus is an important factor in assuring accuracy. For example,

5、 the length of the graduated portions of graduated cylinders should be not less than five times the inside diameter, and the tips of burets and pipets should restrict the outflow rate to not more than 500 L per second.容量仪器的设计是保证准确度的重要因素。例如，量筒刻度部分的长度应不小于内径的5倍，滴定管和移液管的滴嘴应能限制流速不超过500L每秒。Standards of Ac

6、curacy The capacity tolerances for volumetric flasks, transfer pipets, and burets are those accepted by the National Institute of Standards and Technology (Class A),1 as indicated in the accompanying tables. Use Class A volumetric apparatus unless otherwise specified in the individual monograph. For

7、 plastic volumetric apparatus the accepted capacity tolerances are Class B.2准确度标准 - 容量瓶、移液管和滴定管的容积误差，应符合NIST（A级）标准（注1），详见附表。如在各论中无另外说明，应使用A级容量仪器。对于塑料容量仪器，可接受容积误差为B级。（注2）The capacity tolerances for measuring (i.e., “graduated”) pipets of up to and including 10-mL capacity are somewhat larger than tho

8、se for the corresponding sizes of transfer pipets, namely, 10, 20, and 30 L for the 2-, 5-, and 10-mL sizes, respectively.10ml及10ml以下的刻度吸管的容积允差比单刻度吸管要大，即对于2ml，5ml和10ml吸管，其允差分别为10ul，20ul和30ul。Transfer and measuring pipets calibrated “to deliver” should be drained in a vertical position and then touch

9、ed against the wall of the receiving vessel to drain the tips. Volume readings on burets should be estimated to the nearest 0.01 mL for 25- and 50-mL burets, and to the nearest 0.005 mL for 5- and 10-mL burets. Pipets calibrated “to contain” are called for in special cases, generally for measuring v

10、iscous fluids like syrups; however, a volumetric flask may be substituted for a “to contain” pipet. In such cases, the pipet or flask should be washed clean, after draining, and the washings added to the measured portion.移取和测量用移液管，如校正为“移出”应在垂直的位置使其流出，将滴嘴接触接收容器内壁以使液滴流下。滴定管的体积读数应估计至最近的0.01ml（对于25ml和50

11、ml的滴定管），和最近的0.005ml（对于5ml和10ml滴定管）。校正为“保留”移液管称为特殊情况，一般用于测量粘性液体，如糖浆，当然，容量瓶中配制溶液时也可能会用到“保留”类型移液管，这种情况下，移液管或容量瓶应清洗干净，在流出后，将清洗液加入测量部分。Volumetric Flasks 容量瓶Designated volume, mL标识容积1025501002505001000Limit of error, mL允差mL0.020.030.050.080.120.200.30Limit of error, %允差%0.200.120.100.080.050.040.03Transfe

12、r Pipets 移液管Designated volume, mL标识容积125102550100Limit of error, mL允差mL0.0060.0060.010.020.030.050.08Limit of error, %允差%0.600.300.200.200.120.100.08Burets 滴定管Designated volume, mL标示容积10 (micro type 微量)2550Subdivisions, Ml最小刻度0.020.10.1Limit of error, mL允差0.020.030.05 1 See ASTM 288-06, ASTM E 287-02, AST